With car-sharing becoming so popular that it’s attracting patent trolls, it’s a logical extension to the concept to have app-enabled bike-sharing schemes, too. And wouldn’t you know it? Here come two at once.

A couple of a weeks ago, a San Francisco outfit called Mesh Motion hit its $120,000 Kickstarter goal for its Bitlock product. And on Tuesday, British-German outfit VeloLock said it had passed its own £50,000 ($81,000) Lock8 Kickstarter goal ahead of schedule, and also picked up additional funding from Horizon Ventures and Otto Capital.

Both Bitlock and Lock8 are bicycle locks that rely on smartphones rather than physical keys to unlock them. And both smartphone apps allow the sharing of the bike with friends and, in theory, through commercial bike-sharing schemes.

However, there are significant differences – in a nutshell, Lock8 ($149, shipping in July 2014) is a more advanced device than Bitlock ($129, shipping in August 2014). Its battery uses induction charging to get juiced up by the act of cycling, rather than needing replacement at some point. Lock8 features GPS, which is handy for the rental scheme and also if the bike gets stolen with the lock still attached.

True, thieves usually ditch the lock when they steal a bike (which is why Bitlock opts to use the phone’s GPS), but Lock8 also has an ear-shredding alarm (paired with push notifications) that gets activated when someone tries to remove the lock – the device has a smart cable and motion sensors to detect bolt-cutters, saws, angle grinders and the like, and even temperature sensors to set off the alarm when a thief whips out his trusty blowtorch or tries freezing the lock.

Bitlock comes with an activity monitor for those who want to count calories, but Lock8 counters that with an optional subscription service that gives the owner a way to rent out her bike, with Lock8 keeping 10 percent commission for rentals. In theory, the owner can recoup her costs for buying the device.

And if your phone’s dead? Lock8 will also provide a key fob for such cases, while Bitlock can generate a binary digit code at registration that the owner can then write onto a piece of paper and carry around (the lock has “1” and “0” buttons).

Both Mesh Motion and VeloLock are touting the sharing-economy potential of their locks and noting how ideal they are for city-wide schemes. Neither has actually secured any yet, though, which is fair enough as neither will ship before mid-2014. I suspect there may be a few more competitors on the block by that point.

This post was updated at 5.40am PT to reflect the fact that Bitlock’s Bluetooth unlocking feature is also shared by Lock8.